Post by MyalPost by MyalPost by DanPost by MyalWhen we lived on the farm my Dad owned , we had windmills pumping
water
Post by MyalPost by Danfor
Post by Myalus , it was years before we had power , and even then , the mills
stayed
Post by Myal.
Post by DanPost by MyalAre windmills impracticle where you are ?
Windmills are for immediately subsurface water, which was plentiful
before
Post by MyalPost by Danpowered pumps lowered water tables. Could still work, depending on
the source of your aquifer.
Dan
The bores we had were 70 and 90 foot deep , I am not sure of your idea of
imeadiate sub surface water , how deep are you talking ?
Myal
In many (most?) areas, several hundred feet is the norm. In heavy
agricultural areas
using subsurface water, thousands of feet are not uncommon.
Dan
Hmmmm. I would have phrased that "In SOME areas ...". Depends on
where yah live, of course. And the source of your info. Not all
sources are equally valid.
Your post sounded like it hinted at a bit more depth and effects (on
average across the country) upon the water tables of farm irrigation
than I'd expect from what I've seen. Having lived in a great many
different places.
So I did a check with the USDA. They do not collect the relavent data
on every state. But do occassionally run a survey of the following
states. The farmers themselves provide the data. Who would know
better? After all, it's their wells, they paid to have them dug.
There were about 100,000 respondents, reporting a bit over 300,000
irrigating wells on their properties.
The following are the AVERAGES. by state: First number is the average
to strike water. Second number is the average actual pumping depth
used.
Arizona.................................. 147..... 229
Arkansas............................... 49 ..... 82
California............................... 97 ..... 157
Colorado .............................. 66 ..... 107
Florida.................................. 73 ..... 128
Georgia ................................ 88 ..... 152
Idaho.................................... 126 ..... 181
Illinois................................... 29 ..... 62
Kansas................................. 111 ..... 173
Louisiana ............................. 49 ..... 83
Michigan .............................. 32 ..... 59
Minnesota ............................ 38 ..... 76
Mississippi ........................... 35 ..... 64
Missouri ................................ 19 ..... 47
Montana................................. 42 ..... 77
Nebraska ............................... 73 ..... 122
Nevada .................................. 90 ..... 160
New Mexico ..........................101 ..... 159
North Dakota......................... 29 ..... 55
Oklahoma ............................. 103 .....198
Oregon................................... 70 ..... 136
South Dakota......................... 39 ..... 78
Texas ....................................159 .....219
Utah ...................................... 72 .....122
Washington .......................... 87 .....151
Wisconsin............................. 38 ..... 82
Wyoming .............................. 70 ..... 120
Keep in mind a few things.
First you will note that the pump suctions are located below the
actual water table, point at which you strike water. A common
practice. i.e. Note the figures for Minnesota, where I live. On
average they strike the water table at 38 foot, but locate their pump
suction at 76 foot.
Why? Consider my own residential well suction is located well below
the normal water table. I simply don't feel like having to put in an
emergency call to a well driller during a dry.year. So my suction is
located at the original driller's best estimate of the "never fail"
level. As that fellow has spent a lifetime drilling wells in this
particular area (he's my age, mid 50's), I am pretty confident in his
advice.
Also note that the wells are often drilled even deeper than the
location of the pump suction. There are a number of reasons to do
this. Among others, to establish that you've hit the true water
table, as versus a shallow underground stream, how deep and reliable
of volume is the water source, to determine the soil structure above
and below the well pumping point, establish a silt collection pit,
etc. Reasons are multiple and varied according to area. But the
result is that, for instance, the average farm irrigation well in
Arizona is drilled to a depth of 422 foot, even tho the pump suction
is located at only about half that. Net result is that if you only
look at the figures of how deep the well is drilled, it can be
misleading as to where the normal water table is located. I left
those figures out for that very reason.
Also keep in mind the the figures represent data for farms requiring
irrigation wells and does not speak to how deep some homeowner may
have to dig in his area to find water. i.e. Here in Minnesota the vast
majority of farms are located in the southern part of the state, in
relatively well drainned areas. As compared to a lot of places in the
state where yah can strike water by driving a sharp stick in the
ground with a hammer.
Also, consider your comments alluding to the fact that agricultural
wells can considerable affect water table levels. True enough ...
they CAN. Depending on area and available water sources. But in many
areas there is a LOT of water. And such farm irrigation has from
little to no measureable effect.
Bob